The present invention relates to a control device and a process utilizing the control device for aligning, in the running direction, an endless belt revolving around a driven roller and a deflecting roller.
In the course of rotation of endless belts guided over two or more rollers, difficulties regarding the straight running of belts are known to arise after a relatively long operating period. Reasons for the belts running out of alignment primarily include deviations in the concentricities of the rollers, a deficient parallel alignment of the roller axles, varying heating at different points on the individual belt, varying belt abrasion, an uneven load distribution on the belt and the like.
The problem is remedied to a certain extent by so-called cambered rollers, as compared to cylindrical rollers or cylinders. Cambered rollers are rollers or cylinders which possess a non-uniform diameter over their length and, for example, have a larger diameter in the roller or cylinder center than near the end faces of the roller or cylinder. However, as with cylindrical rollers, even when the rollers are designed in this way, it is necessary to make them as identical as possible with maximum precision, thus making it considerably more expensive to produce the rollers because of the high precision required.